Berry harvesting, particularly blueberry harvesting, is often performed by hand-picking or by raking through the berry bushes. This is a tedious work particularly for wild blueberries, which bushes barely extend a couple of centimeters above the ground.
Over the years, mechanical harvesters have been proposed to increase the speed or efficiency at which the harvesting is performed. Generally, such mechanical harvesters comprise a rake for raking the bushes, a collector for receiving and collecting the berries as they are detached from the bushes by the rake, and a transporting mean such as a conveyor for transporting the berries from the collector to a container. In order to increase efficiency, mechanical harvesters usually have the capacity to move along the berry field, in order to pick up berries in most or all of the bushes.
Current mechanical harvesters usually advance over a row of berry bushes while raking the branches of the bushes. This raking movement involves a sliding of the branches between the teeth of the rake under the movement of the harvester. Since the space between the rake teeth is usually smaller that the mean diameter of a berry, the berries are retained on the rake. Their transfer towards the collector is usually made by tilting up the rake, orienting it substantially vertically so that gravity will pull the berries toward the base of the rake, where the collector can collect them before they are move toward the transporting mean.
While such harvesters are efficient in harvesting low bushes such as wild blueberry bushes, one problem is that the rake must be periodically cleaned to remove the bush debris, such as broken branches, leaves and berries, that stuck in between the teeth during operation. Without periodical cleaning during harvesting, such bush debris are accumulating between the rake teeth, reducing the efficiency of the raking and the harvesting.
One way to perform the periodical cleaning of the rake's teeth during harvesting is by adding a slidable cleaning bar to the rake portion of the harvester. Such cleaning bar is mounted over the rake, and usually adapted to slidably move from the base to the end of the teeth of the rake. Gravity ensure that the cleaning bar will stay in contact with the rake teeth underneath it during the sliding movement. However, while such a cleaning of the rake teeth is improving the subsequent raking of further bushes, it results in the loss of valuable berries that will either be squashed or fall on the ground as a result of the sliding action of the cleaning bar. Therefore, the cleaning of the rake causes an appreciable loss of berries, while improving the global harvesting process by periodically ensuring that the rake is clean for raking through the bushes. Still, it would be highly desirable to have a system allowing for the collection of a maximum of berries, while reducing the loss of berries to a minimum, thereby optimizing the mechanized harvesting process.